Federal, state and local governmental bodies reacting to constituent pressures have instituted a series of laws and regulations aimed at preventing the continued contamination of the environment. These laws and regulations encompass numerous minerals and chemicals regarded as contaminants and/or hazardous materials, and affect many different industries. The content of these minerals and chemicals in effluent streams is often restricted to very stringent levels. Compliance with the increasingly stringent regulations is one of the greatest challenges for industry to meet. Such compliance can become extremely costly, even to a point where competitive pricing can be jeopardized.
Dissolved silver (Ag.sub.2) is one hazardous material that is regulated by the Environmental Protection Agency (EPA). The EPA effluent limit for silver in water is 5 ppm or below. It is therefore important that industries discharging or otherwise generating solutions or waste water containing dissolved silver monitor for this low silver concentration.
A variety of methods and devices are available to test effluent solutions for contaminants. For example, for testing the concentration of silver in photo processing and industrial solutions or waste waters various methods and devices have been disclosed using such things as silver sensitive testing papers, copper strips or wire, color metric titration, spectrography and atomic absorption.
Many of these previously disclosed devices can be extremely complex and expensive to employ. Some can only be used under exacting laboratory conditions. In addition, generic copper strips used in other methods vary in quality and can quickly oxidize thereby leading to inconsistent and unreliable results. These factors contribute to inconsistent readings and test performance.
There remains a need, therefore, for simple, low cost, reliable methods and devices that can be readily and remotely employed to test for silver as a contaminant in various industrial solutions and waste waters, particularly those dealing with photo processing. Such methods and devices should be sensitive to low concentrations of silver, particularly those at or near compliance levels.